Apoptosis was promoted at a nonpermissive temperature in DNA replication-defective temperature-sensitive mutants of mouse FM3A cells.
Apoptosis was promoted at the nonpermissive temperature in some temperature-sensitive (ts) mutant strains of mouse FM3A cells deficient in initiation of DNA replication. We examined expression of cell cycle regulation genes in the four ts mutant strains and found that two strains, tsFT107 and tsFT111, exhibited marked accumulation of p53 protein by a posttranscriptional mechanism at 16 h after temperature up-shift. These two strains also exhibited high levels of p21 mRNA expression, repression of cyclin A and D1 mRNAs, and obvious accumulation of underphosphorylated retinoblastoma protein. Only these two strains died by apoptosis at day 3 after up-shift, although no change was observed in the level of bax mRNA. These results suggest the existence of two types of responses after temperature up-shift in the four temperature-sensitive cell strains of the initiation of DNA replication: one type directs inappropriate DNA replication that then may produce endogenous DNA damage, p53-mediated cell cycle arrest, and subsequent apoptosis, while the other type exhibits only the p53-independent cell cycle arrest.
Yamauchi
Y
Y
Biochemical Research Institute, Morinaga Milk Industry, Co., Ltd., 5-1-83, Higashihara, Zama, Kanagawa, 228, Japan.
Tanaka
A
A
Yamaguchi
K
K
Kobayashi
M
M
Shimamura
S
S
Hanaoka
F
F
D000818:Animals; D017209:Apoptosis; D002277:Carcinoma; D002453:Cell Cycle / Q000235:genetics*; D002460:Cell Line; D002470:Cell Survival; D019925:Cyclin A / Q000235:genetics; D019938:Cyclin D1 / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics; D053938:DNA Fragmentation; D004261:DNA Replication / Q000235:genetics / Q000502:physiology*; D008325:Mammary Neoplasms, Experimental; D051379:Mice; D009154:Mutation; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger / Q000032:analysis; D016160:Retinoblastoma Protein / Q000378:metabolism; D013696:Temperature; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D014466:Ultraviolet Rays; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; C493957:Cdkn1a protein, mouse; D019925:Cyclin A; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D019938:Cyclin D1